Scilab Function
Last update : 12/1/2004

nehari - Nehari approximant

### Calling Sequence

  `[x]=nehari(R [,tol])`

### Parameters

- `R`: linear system (`syslin` list)
- `x`: linear system (`syslin` list)
- `tol`: optional threshold

### Description

`[x]=nehari(R [,tol])returns` the Nehari approximant of `R`.

`R` = linear system in state-space representation (`syslin` list).

`R` is strictly proper and `- R~` is stable (i.e. `R` is anti stable).

        || R - X ||oo = min || R - Y ||oo
                      Y in Hoo